4.
Irrigation

Theory:

All living beings need water to live.Water is important for proper growth and development of every living organism.

Water is an essential element in agriculture.

The supply of water to crops at regular intervals is called irrigation.

Water is an essential element in agriculture for the following reasons:

Water is absorbed by the plant roots. Along with water,minerals and fertilisers are also absorbed.

Plants contain nearly 90% water.

Water is essential because germination of seeds does not take place under dry conditions.

Nutrients dissolved in water are transported to each and every part of the plants also through water.

To maintain the moisture of the soil for healthy crop growth, fields have to be wateredregularly.

The time and frequency of irrigation varies from crop to crop, soil to soil and season to season. In summer, the frequency of watering is higher when compared to other seasons.

Sources of irrigation:

The sources of water for irrigation are — wells, tubewells, ponds, lakes, rivers, dams and canals.

Traditional Methods of Irrigation:

The water available in wells, lakes and canals need to be lifted up to the field throug different methods in different regions.

Cattle or human labour is used in these methods. So these methods are cheaper, but less efficient. Examples of traditional ways of irrigation are:(i) moat (pulley-system)(ii) dhekli, and(iii) rahat (Lever system)

Modern Methods of Irrigation:

Modern methods of irrigation uses electricity and engineering to economically and efficiently use the water. Since it involves power and machinery, it incurs a cost.The following are the major methods of modern irrigation

(i) Sprinkler irrigation system:

In this system, the water is sprinkled through small tubes and rotating nozzles attached to a major pipe line with water. When water is forced through the smaller tubes from the main pipe line, it activates the nozzles and make the water sprinkle to the adjoining area. Sprinkler is very useful for lawns, coffee plantation and several other crops.Sprinkler system is particularly useful in areas surface uneven.

(ii) Drip irrigation system:

In this system, the water is made to fall drop by drop near the roots. So it is called drip system. This system best suits for watering fruit trees and gardens. In this system, water is not wasted. It is a boon for farmers in the dry regions, with poor water resources.